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Crystal substructure and physical properties of the superconducting phase Bi/sub 4/(Sr,Cr)/sub 6/Cu/sub 4/O/sub 16/. mu. /sub x/

Journal Article · · Phys. Rev. B: Condens. Matter; (United States)
We have isolated a high-T/sub c/ phase in the Bi-Sr-Ca-Cu-O system of composition Bi/sub 4/(Sr,Ca)/sub 6/Cu/sub 4/O/sub 16/..mu../sub x/. The crystal substructure has a tetragonal unit cell (a = 3.817 A, c = 30.6 A) with similarities to both the oxygen-defect perovskites YBa/sub 2/Cu/sub 3/O/sub 7/..sqrt../sub x/ and the K/sub 2/NiF/sub 4/ structure of La/sub 2/CuO/sub 4/. The oxygen content, determined by titration and thermogravimetric analysis (TGA) experiments, corresponds to a formal oxidation state Cu(2.15). Oxygen can be reversibly depleted in an argon ambient in an amount corresponding to the reduction of the Cu(III) into Cu(II). The compound has a metalliclike resistance above its T/sub c/ near 85 K. Processing this precursor compound by heating to temperatures near its melting point (885 /sup 0/C) produces a sharp resistivity drop near 110 K that we show by ac susceptibility and Meissner effect is due to a superconducting transition.
Research Organization:
Bellcore, 331 Newman Springs Road, Red Bank, New Jersey 07701
OSTI ID:
5000097
Journal Information:
Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 37:16; ISSN PRBMD
Country of Publication:
United States
Language:
English